摘要:

The aims of the study were (1) to compare the anticaries efficacy of a silica abrasive dentifrice containing 0.24% NaF and 0.3% triclosan/2.0% copolymer with a similar dentifrice without the triclosan/copolymer and (2) to study any disturbance of the oral mucosa associated with the test formulation. A double-blind, random, unsupervised, 30-month longitudinal clinical trial was conducted on 3,462 children who were initially 11–13 years of age. Two trained and calibrated dentists each examined approximately half the children. Examinations were undertaken at baseline, 15 months and 30 months. No significant differences were found between the DFS or DFT mean increments for the two dentifrice groups after 15 or 30 months. At 30 months the 90% confidence interval for the ratio of the mean increments satisfied the ADA criteria for equivalence. It is concluded that a 0.24% NaF/silica abrasive dentifrice containing 0.3% triclosan/2.0% > copolymer is equivalent in its anticaries efficacy to a similar dentifrice without the addition of triclosan/copolymer. No side effects attributable to the test or control dentifrices were observed at any time during the stud

ISSN:0008-6568    

DOI:10.1159/000262063

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A double-blind 3-year clinical trial was conducted in a nonfluoridated water community in which 354 schoolchildren aged 9–10 years were assigned randomly to three groups (A, B and C) and subjected to a treatment with 1 of 3 different concentrations of amine fluoride solution every 2 months. Clinical examinations were conducted at baseline and after 1, 2, and 3 years. For group A (positive control) receiving topical applications of amine fluoride solution (1%), the 3-year DMFT and DMFS increments were 4.0+ (SD) 2.7 and 8.5 ± 5.6, respectively. For group B (0.5% F), the DMFT and DMFS increments were 4.4 ± 3.0 and 8.4 ± 5.7, respectively; these differences being statistically not significant. The mean caries increments in group C (0.25% F) were 5.1 ± 2.9 for DMFT and 10.0+5.5 for DMFS. The differences in incremental caries scores between group C and groups A or B were statistically significant (p < 0.05). Thus, the amine fluoride solution, in which the fluoride content was reduced by half, provided similar caries reductions in schoolchildren as did a standard amine fluoride solution with 1

ISSN:0008-6568    

DOI:10.1159/000262064

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The aim of this investigation was to study the effect of sugar-free chewing gums containing various amounts of urea on the pH recovery in dental plaque. Three plaque-measuring methods were used, i.e., the telemetric, the microtouch, and the sampling methods. The subjects who had refrained from toothbrushing for 3–7 days rinsed with either 10 or 50% (w/v) sucrose solutions and then chewed for 10 min: (1) one piece of chewing gum in a series of six tests in which the urea content increased from 10 to 80 mg per piece of gum; (2) one or two pieces of gum containing 20 mg urea, and (3) one, two, or three pieces of gum, one after the other, containing 20 mg urea. In some of the test series, a conventional sugarless gum was used as a control. A quick rise in plaque pH was found with all urea-containing chewing gums within the first minutes of chewing, and neutralization continued during the whole 10-min chewing periods. Higher concentrations of urea resulted in more pronounced pH recovery. Slightly higher plaque pH values were found when chewing on two pieces at a time of a 20-mg urea gum was compared with only one piece. Significantly higher pH values were recorded when using three pieces of chewing gum, one after the other (10+10+10 min), as compared with two pieces (10+10 min) or just one piece (10 min). In conclusion, all sugar-free chewing gums tested, particularly the urea-containing ones, initiated a pronounced pH recovery in dental plaque when chewed after a sucrose rinse. Variations were seen depending on the amount of urea in the gum and on the number of pieces chewe

ISSN:0008-6568    

DOI:10.1159/000262065

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Inhibition of dental plaque acidogenicity by chlorhexidine (CHX) mouthrinses has been ascribed to a long-lasting bacteriostatic effect due to binding of CHX to oral surface structures combined with a slow release rate from the binding sites. The present aims were to study the effects of CHX-containing mouthrinses on the viability and glycolytic activity of established plaque in order to assess the bactericidal versus the bacteriostatic effects. Following 2 days of plaque accumulation, three groups of 10 students rinsed with either 12.0 mMNaF, 0.55 mMCHX plus NaF, or with 2.2 mM CHX plus NaF Plaque samples were collected before and 90 min after mouthrinsing. The pH in pooled pre- and post-rinse plaque samples was recorded before and up to 10 min after the addition of D-[U-14C]glucose. Total colony-forming units in each sample were determined. High-performance liquid chromatography analyses showed lactate to be the major extracellular glycolytic metabolite in all samples. CHX-NaF markedly reduced the colony-forming units, the pH fall from fermentation of glucose, as well as glucose consumption and lactate formation, whereas NaF alone exhibited no such effects. The reduction of glucose consumption by the CHX-NaF mouthrinses corresponded to the reduction of colony-forming units, indicating no bacteriostatic effect. The plaque pH in vivo was monitored in each student 90 min after mouthrinsing with the test solutions prior to and up to 1 h after a sucrose mouthrinse using touch microelectrodes. The CHX-NaF mouthrinses reduced the fall in pH significantly (p < 0.05) as compared with the NaF mouthrinse. The results suggested that the reduced acid formation by dental plaque following a CHX mouthrinse is due to a bactericidal effect rather than a long-lasting bacteriostatic action.

ISSN:0008-6568    

DOI:10.1159/000262066

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The effect of an antibacterial varnish (Cervitec®) on the levels of mutans streptococci in plaque adjacent to bonded orthodontic brackets was evaluated in 18 children using a split-mouth technique with a placebo varnish control. The test varnish contained 1% chlorhexidine and 1% thymol as active ingredients. Both varnishes were applied on four occasions during a 3-month period, and plaque was subsequently collected between 1 week and 6 months after the onset of treatment. All teeth involved in the study were carefully examined and clinically assessed for enamel demineralization prior to onset of the fixed appliances and immediately after debonding. The results showed a more frequent growth of mutans streptococci in the dental plaque collected from placebo-treated quadrants as compared with the test quadrants on all sampling occasions. The proportion of mutans streptococci within the plaque micro flora was significantly (p < 0.05–0.01) lower on the test sides than on the opposite sides at the 1-week and 1-month examinations. The incidence of incipient enamel lesions around the brackets and along the gingival margin was generally low, and no differences were found between the test and placebo varnish treated quandrants at the time of debonding. The results suggest that mutans streptococci in plaque from orthodontic patients can be suppressed effectively by topical applications of an antibacterial varni

ISSN:0008-6568    

DOI:10.1159/000262067

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Suspensions of the cariogenic bacterium, Streptococcus mutans were treated with either toluidine blue·or aluminium disulphonated phthalocyanine and then exposed to light from a helium-neon or gallium-aluminium-arsenide laser, respectively, after passing through demineralized dentine slices. Bacteria were also embedded in a collagen matrix prior to sensitization and exposure to the laser light. When dentine slices were interposed between the laser light and the bacterial suspension, substantial kills (107 CFU) were achieved at energy doses of 876, 1,752, and 3,504 mJ with the helium-neon laser and of 1,188, 2,376, and 4,752 mJ with the gallium-aluminium-arsenide laser. There was no apparent relationship between the extent of killing and the degree of demineralization of the dentine. Prolonging the exposure of the sensitized bacteria to the laser light increased the kill achieved. Substantial numbers (108 to 1010 CFU) of S. mutans were also killed when embedded in a collagen matrix and exposed to 438 and 1,314 mJ of helium-neon laser light and 594 and 1,782 mJ of light from the gallium-aluminium-arsenide laser. These results imply that lethal photosensitization may be effective at killing S. mutans in a carious lesion, even when the organism is embedded in demineralized dentine

ISSN:0008-6568    

DOI:10.1159/000262068

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Secondary caries is one of the major reasons causing restoration failure; however, little is known of its microbial etiology, mainly because of the difficulties in eliminating bacterial contamination during collection and sample preparation. Therefore, the purpose of this study was to investigate the feasibility of immunofluorescent techniques and confocal laser scanning microscopy for identification and quantification of bacteria in secondary carious lesions. Thirty-six extracted human teeth, clinically diagnosed as having secondary caries, were used in the study. The teeth were sectioned in half across the secondary carious lesion. One half of each tooth was processed using the Brown and Hopps histologic staining method for bacterial detection. Sections (100 μm thick) were obtained from the other half of each tooth for immunofluorescence labeling to detect and identify mutans streptococci in the subsurface of the lesion using confocal imaging techniques. Mutans streptococci were detected in 88.9% of the samples analyzed with the immunofluorescent technique. The Brown and Hopps histopathologic examination demonstrated evidence of bacteria in 94.4% of the samples. In addition, quantification of bacteria was conducted by digitalization of confocal images. The results indicated that the immunofluorescence confocal laser scanning microscopy technique was sensitive and specific for detection and quantification of mutans streptococci in secondary carious lesions

ISSN:0008-6568    

DOI:10.1159/000262069

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The purpose of this article is to compare various model systems for the production of in vitro root caries and to assess their ability to simulate the naturally occurring root caries process. Partially saturated buffer models and gel models were evaluated using polarized light microscopy and both qualitative and quantitative microradiography. All model systems showed very similar lesion formation when examined under polarized light. When microradiographs were compared, the systems which contained fluoride, showed clear radiopaque bands within the lesion. The bands, which occurred only in the presence of fluoride, appeared to be due to remineralization. When using an in vitro system that simulates the natural root caries process, it is imperative to understand the components of the particular model, as well as its limitations, and to be aware of the need for more than one evaluative technique.

ISSN:0008-6568    

DOI:10.1159/000262070

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Synthetic hydroxyapatite and human dental enamel (polished and non-polished) were subjected to various fluoride applications, i.e., using solutions of sodium fluoride (NaF), acidulated phosphate fluoride (APF), and stannous fluoride (SnF2). Treatment with APF has a strong influence on the morphology of the apatite. All fluorides, in particular SnF2, make the enamel surfaces more hydrophobic. NaF and APF applications slightly alter the electrokinetic potentials of the surfaces, but SnF2 renders them much more negatively charged. The adsorption of the proteins lysozyme and α-lactalbumin on these surfaces can be explained in terms of electrostatic and hydrophobic interactions between the proteins and the sorbent surfaces

ISSN:0008-6568    

DOI:10.1159/000262071

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The present study was undertaken to determine the fluoride distribution profile in rat molar cementum with age in relation to fluoride in drinking water. Fifty-four female Wistar rats were used for the experiment. Before the experiment 6 rats were killed under chloroform anesthesia at 4 weeks of age as controls. The remaining 48 rats were divided into two groups: a control group given distilled water and the other group given water containing 100 ppm fluoride ad libitum. Six rats from each group were killed at the ages of 6,12, 24, and 48 weeks. The fluoride distribution in the molar cementum was analyzed from the surface to the cementodentinal junction by abrasive microsampling. The fluoride concentrations in molar cementum from control rats on distilled water remained relatively constant until 24 weeks. A small increase then occurred between 24 and 48 weeks. The fluoride concentration in cementum from rats drinking water containing 100 ppm fluoride increased markedly with age, both in outer and inner regions of the molar cementum for all rats. On the other hand, the fluoride concentration in the cementum of older rats drinking water with 100 ppm fluoride was significantly higher in the outer than in the inner region of the cementum. It was concluded that the fluoride distribution in rat molar cementum may increase throughout life in relation to the fluoride level in the drinking water.

ISSN:0008-6568    

DOI:10.1159/000262072

出版商:S. Karger AG    

年代:1995

数据来源: Karger